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circuit

Solar energy fixed power point boost converter

Modify a standard LM2577S boost converter module to be used as a fixed power point converter using the available solar energy efficiently.

LM2577S boost converter with fixed power point circuit

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circuit tips

Atmel ICE header adapter

The Atmel ICE is a fantastic tool for programming and debugging AVR and Atmel ARM chips. However, the included cable has a connector with a pin pitch of only 1.27mm. I made a header adapter to make this Atmel ICE more useful for normal spaced 2.54mm connectors.

Atmel ICE with header adapter

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circuit

Countdown timer with random intervals

After the random timer based on an Attiny24 I have build a larger version of the random countdown timer. The Attiny24 had a single channel and two potentiometers. In this countdown timer the number of outputs have been increased from 1 to 8. The potentiometers have been replaced by a 2×16 HD44780 LCD screen and a rotary encoder.

Multichanel random timer with LCD and rotary encoder

With this random countdown timer circuit you can turn on and off 8 outputs. The outputs are, while randomly turned on and off, still grouped together meaning that as a group that at the beginning and half way the countdown timer cycle they are all on or off at the same time.

With this circuit you can simulate people turning on and off internal house lighting in a street on a model railroad track. Read on and see it in action.

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circuit software

Time server using 1PPS GPS receiver

What is a time server? A time server gets its time from a reference time source. That source can be a another time server, a local time source such as a rubidium or cesium atomic clock. In this post I make an USB GPS receiver for a Linux time server using cheap available components. After assembling the GPS module I give instructions on how to configure the Linux NTP daemon to use this module. The GPS receiver gets its time signal from the GPS satellite network. Its longtime time drift is about 0 seconds. This is possible because the GPS time signals are constantly adjusted to keep very accurate time needed for navigation.

Finished USB GPS 1PPS receiver

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circuit

Joule thief AA battery led circuit

Here I present to you a single AA battery led circuit. This circuit is a variant of the Joule thief in that it contains 2 transistors and a simple standard 2 lead inductor instead of a hand wound 2 wire inductor.

white led circuit joule thief detail

You can use it as a white led torch. You can use a fresh AA battery, but the circuit is special in that it accepts empty batteries. Down to 0.7 volts. Do you have a box of empty batteries? They are still useful to power this led circuit.

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circuit

TDA2030A Amplifier DIY Kit Schematic and soldering howto

This howto shows you the schematic of a popular TDA2030A amplifier DIY kit which is sold on eBay and other places.

tda2030a finished BTL amplifier

After ordering the kit on eBay (search for “TDA2030A Audio Power Amplifier DIY Kit”) I received a version 1.0 PCB made by XY HI-FI with components and a short Chinese manual on what was needed to solder the kit in stereo mode (OCL) or in mono mode (BTL or bridge).

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circuit

Random timer circuit using a Attiny24A

This random timer circuit is based on a Atmel ATTINY24 avr driving one power relay. You can use this circuit to switch on and off other circuits randomly. For example, when using this circuit on a model railroad you can turn on and off parts of the animated or moving scenery to create a more dynamic view.

attiny24 random timer circuit prototype

This circuit was designed to be used on a modular model railroad. This model railroad contains different flashing light on ambulances, police cars and fire engines. These lights are on all the time, with this circuit I hope to keep visitors of a model railroad exposition more interested while watching all the action.

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circuit

$0.02 SMD LED tester

Soldering a lot of SMD leds? Never sure what polarity the smd led has? Make this simple SMD LED tester.

Take a look in your used battery box and search for a 9V PP3 battery. Solder any resistor with a value between 470 ohms and 10K onto the battery terminals.

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circuit

Supercapacitor red LED rear bicycle light

Modern rear lights use AA batteries that last very long, but still need to be replaced once in a while. Replacing is simple, but take time.

bicycle rear light modded with powerfull red led and super capacitor

Here is a simple circuit that lets you use your dynamo of your bicycle to power the rear light.

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circuit

S88N decoder 8 channel model railroad block occupancy detector

This S88 decoder model railroad block occupancy detector can be used to automate your model railroad with software running on your computer.